43,124 research outputs found
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A survey of nearby galaxies for CO
We have made a survey of the nuclei of 81 galaxies for the 1-) line of CO. 38 of the galaxies are from a complete sample with recession velocity ≦400 km s-1 and 21-cm line strength ≧10-27 Wm-2, and the remainder represent nearby galaxies with weaker or no HI, early-type galaxies (E/SO/Sa) with detected HI and active/infrared galaxies.
Galaxies with strong CO lines like M82, NGC253 and IC342 are exceedingly rare: all the galaxies we observed are weaker than 0/2K except the irregular galaxy DDO133 with T*A=0.22K. We have new, confirmed detections of two other irregular galaxies, IC10 and Pegasus, at a weaker level, and unconfirmed detections of the irregular NGC3109 and the nearest Type I Seyfert galaxy NGC4051. We have confirmed the existence of CO in the nucleus of NGC6946 and obtained spectra of new positions in M82 and NGC253
Gravitational Correction to Running of Gauge Couplings
We calculate the contribution of graviton exchange to the running of gauge
couplings at lowest non-trivial order in perturbation theory. Including this
contribution in a theory that features coupling constant unification does not
upset this unification, but rather shifts the unification scale. When
extrapolated formally, the gravitational correction renders all gauge couplings
asymptotically free.Comment: 4 pages, 2 figures; v2: Clarified awkward sentences and notations.
Corrected typos. Added references and discussion thereof in introduction.
Minor copy editting changes to agree with version to be published in Physical
Review Letter
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An Evaluation of a Battery of Functional and Structural Tests as Predictors of Likely Risk of Progression of Age-Related Macular Degeneration.
Purpose: To evaluate the ability of visual function and structural tests to identify the likely risk of progression from early/intermediate to advanced AMD, using the Age-Related Eye Disease Study (AREDS) simplified scale as a surrogate for risk of progression. The secondary aim was to determine the relationship between disease severity grade and the observed functional and structural deficits. Methods: A total of 100 participants whose AMD status varied from early to advanced were recruited. Visual function was assessed using cone dark adaptation, 14 Hz flicker and chromatic threshold tests and retinal structure was assessed by measuring drusen volume and macular thickness. The predictive value of the tests was estimated using ordinal regression analysis. Group comparisons were assessed using analysis of covariance. Results: Change in cone dark adaptation (cone Ď„) and yellow-blue (YB) chromatic sensitivity were independent predictors for AMD progression risk (cone Ď„, pseudo R2 = 0.35, P < 0.001; YB chromatic threshold, pseudo R2 = 0.16, P < 0.001). The only structural predictor was foveal thickness (R2 = 0.05, P = 0.047). Chromatic sensitivity and cone dark adaptation were also the best functional tests at distinguishing between severity groups. Drusen characteristics clearly differentiated between participants with early and advanced disease, but were not able to differentiate between those with early AMD and controls. Mean differences in retinal thickness existed between severity groups at the foveal (P = 0.040) and inner (P = 0.001) subfields. Conclusions: This study indicates that cone Ď„, YB chromatic threshold and foveal thickness are independent predictors of likely risk of AMD progression
Application of Osteopathic Manipulative Medicine to Ameliorate Sepsis Induced Ileus
Graduate
Basi
Emission lines and optical continuum in low-luminosity radio galaxies
We present spectroscopic observations of a complete sub-sample of 13
low-luminosity radio galaxies selected from the 2Jy sample. The underlying
continuum in these sources is carefully modelled in order to make a much-needed
comparison between the emission line and continuum properties of FRIs with
those of other classes of radio sources. We find that 5 galaxies in the sample
show a measurable UV excess: 2 of the these sources are BL Lacs and in the
remaining 3 galaxies we argue that the most likely contributor to the UV excess
is a young stellar component. Excluding the BL Lacs, we therefore find that
\~30% of the sample show evidence for young stars, which is similar to the
results obtained for higher luminosity samples. We compare our results with
far-infrared measurements in order to investigate the far-infrared-starburst
link. The nature of the optical-radio correlations is investigated in light of
this new available data and, in contrast to previous studies, we find that the
FRI sources follow the correlations with a similar slope to that found for the
FRIIs. Finally, we compare the luminosity of the emission lines in the FRI and
BL Lac sources and find a significant difference in the [OIII] line
luminosities of the two groups. Our results are discussed in the context of the
unified schemes.Comment: 18 pages, 31 figures, MNRAS in press, (all enquiries to Clive
Tadhunter ([email protected])
Brayton-cycle radioisotope heat-source design study. Phase II /preliminary design/ report
Brayton cycle radioisotope heat source desig
Aboveground Net Primary Productivity in Grazed and Ungrazed pastures: Grazing Optimisation Hypothesis or Local Extinction of Vegetation Species
The controversy that has surrounded herbivory studies in the last few decades prompted our investigation to establish the extent to which herbivore optimisation hypothesis or compensatory growth evidence is real. We used the traditional movable cage method to collect primary productivity data on herbage, functional groups and key individual grass species in various controlled large herbivore treatments in an east African savanna. The herbivore treatments in triplicate blocks included cattle, wild herbivores with and without mega herbivores and combinations of cattle and wild herbivores also with and without mega herbivores. The findings revealed that at herbage level, most grazed treatments (four out of five) had higher productivity than the ungrazed control and three showed grazing optimisation curve at sixth polynomial degree between monthly productivity and grazing intensity (1-g/ng). At functional group level forbs productivity was higher in the ungrazed control than in any of the grazed treatments while at individual grass species level _Themeda triandra_ productivity was higher in all grazed treatments than in ungrazed control. We conclude against presence of herbivore optimisation hypothesis at herbage, functional group and species level because of lack of attributable grazing effect in grazed treatments that matches complex ecological effects in the ungrazed treatment
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